Thanks to NBC News anchor Brian Williams' 19 appearances on Comedy Central's "The Daily Show with Jon Stewart," the host of NBC's new newsmagazine "Rock Center" was able to secure Stewart's appearance on Monday, the night of the show's first broadcast.

As it fell on Halloween, when Stewart would traditionally have been trick-or-treating with his kids, the two discussed their children and their costume habits — Stewart usually wears a hat.

Whille all in good fun, Stewart seemed to object to the light-hearted nature of the early discussion.

"We just had a guy talking about anchor babies, about Syria, about emerging technology in North Korea and you and I are going to talk fun-sized candy?" he asked.

That led into a conversation of Occupy Wall Street, a subject where Williams expressed surprise with Stewart's "exacting" coverage.

Stewart rejected that, and questioned how Williams, a newsman, could think these protests were initiating a new era of protest.

"When did we stop?," Stewart asked.

Of course, as much as the two tried to take it seriously, their mutual admiration and playfulness shone through.

Stewart showed up with a four-pack of warm Budweiser — he claimed to have drank the other two — and opened the segment by mocking the set and the show in general.

The duo also made fun of one another's sock choices and tried to expose the other's lower leg to the audience.

"Brian Williams needs vascular support," Stewart joked.

Williams first show: a series of heavy news stories, a little bit of innocuous banter.